[Rgen] Generalize NSArray.FromNSObject to later use it for other code generation. (#22397)

The NSArray.FromNSObject is used in several parts of the code
generation, for example trampolines will use it too. We generalize the
call so that we can easily do function composition to generate the code.

---------

Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>

Author: mandel-macaque

src/rgen/Microsoft.Macios.Generator/Emitters/BindingSyntaxFactory.ObjCRuntime.cs

@@ -562,17 +562,10 @@ internal static BinaryExpressionSyntax ByteToBool (InvocationExpressionSyntax in
 			.WithExpressionBody (constructor.WithLeadingTrivia (Space));
 
 		// generate: NSArray.FromNSObjects (o => new NSNumber (o), shape);
-		var factoryInvocation = InvocationExpression (MemberAccessExpression (
-			SyntaxKind.SimpleMemberAccessExpression,
-			IdentifierName ("NSArray"),
-			IdentifierName ("FromNSObjects").WithTrailingTrivia (Space))).WithArgumentList (
-			ArgumentList (
-				SeparatedList<ArgumentSyntax> (
-					new SyntaxNodeOrToken [] {
-						Argument (lambdaExpression),
-						Token (SyntaxKind.CommaToken),
-						Argument (IdentifierName (parameter.Name).WithLeadingTrivia (Space))
-					})));
+		var factoryInvocation = NSArrayFromNSObjects ([
+			Argument (lambdaExpression),
+			Argument (IdentifierName (parameter.Name))
+		]);
 
 		var declarator =
 			VariableDeclarator (Identifier (variableName).WithLeadingTrivia (Space).WithTrailingTrivia (Space))

src/rgen/Microsoft.Macios.Generator/Emitters/BindingSyntaxFactory.Runtime.cs

@@ -347,6 +347,23 @@ internal static InvocationExpressionSyntax NSArrayFromHandleFunc (string returnT
 			.WithArgumentList (argumentList);
 	}
 
+	/// <summary>
+	/// Factory method that returns the expression for the NSArray.FromNSObjects invocation.
+	/// </summary>
+	/// <param name="arguments">The arguments to be used with the invocation.</param>
+	/// <returns>The NSArray.FromNSObjects invocation.</returns>
+	internal static InvocationExpressionSyntax NSArrayFromNSObjects (ImmutableArray<ArgumentSyntax> arguments)
+	{
+		var argumentList = ArgumentList (
+			SeparatedList<ArgumentSyntax> (arguments.ToSyntaxNodeOrTokenArray ()));
+
+		return InvocationExpression (MemberAccessExpression (
+			SyntaxKind.SimpleMemberAccessExpression,
+			IdentifierName ("NSArray"),
+			IdentifierName ("FromNSObjects").WithTrailingTrivia (Space)))
+			.WithArgumentList (argumentList);
+	}
+
 	/// <summary>
 	/// Returns the enum extension method needed to get the value of the enum from a NativeHandle.
 	/// </summary>

tests/rgen/Microsoft.Macios.Generator.Tests/Emitters/BindingSyntaxFactoryRuntimeTests.cs

@@ -408,4 +408,33 @@ void SmartEnumGetValueTests (TypeInfo enumType, ImmutableArray<ArgumentSyntax> a
 		Assert.Equal (expectedDeclaration, declaration.ToFullString ());
 	}
 
+	class TestDataNSArrayFromNSObjects : IEnumerable<object []> {
+		public IEnumerator<object []> GetEnumerator ()
+		{
+			yield return [
+				ImmutableArray.Create (
+					Argument (IdentifierName ("arg1"))),
+				"NSArray.FromNSObjects (arg1)"
+			];
+
+			yield return [
+				ImmutableArray.Create (
+					Argument (IdentifierName ("arg1")),
+					Argument (IdentifierName ("arg2")),
+					Argument (IdentifierName ("arg3"))),
+				"NSArray.FromNSObjects (arg1, arg2, arg3)"
+			];
+		}
+
+		IEnumerator IEnumerable.GetEnumerator () => GetEnumerator ();
+	}
+
+	[Theory]
+	[ClassData (typeof (TestDataNSArrayFromNSObjects))]
+	void NSArrayFromNSObjectsTests (ImmutableArray<ArgumentSyntax> arguments, string expectedDeclaration)
+	{
+		var declaration = NSArrayFromNSObjects (arguments);
+		Assert.Equal (expectedDeclaration, declaration.ToFullString ());
+	}
+
 }